1. Field of the Invention
The present invention relates to a wireless communication apparatus which uses a radio wave in a millimeter wave band in communication.
2. Description of the Related Art
As a method for transmitting a high definition video signal using an uncompressed stream in wireless communication, a technique has been known which uses wireless communication in 60 gigahertz (GHz) (millimeter wave) band (refer to Japanese Patent Application Publication No. 2007-524288). Further, in the wireless communication in the millimeter wave band, a radio wave is characterized by its significantly strong straightness, therefore its field intensity is weakened even by a shield with a size of a human body. Thus, there is a problem that communication performance is degraded.
Concerning this problem, Japanese Patent Application Laid-Open No. 2007-235370 discusses a technique in which data volume to be transmitted is controlled according to a radio wave condition, so that image transmission can be executed without interruption. Japanese Patent Application Laid-Open No. 2007-028048 discusses a technique for detecting whether an apparatus is retained by a user and increasing the number of wireless users when the apparatus is retained by the user.
However, the interruption of a radio wave may frequently occur in the wireless communication using the millimeter wave due to its radio property, even under a circumstance in which the interruption does not occur in the conventional wireless communication. For example, the radio wave may be interrupted when an object is passed through between apparatuses communicating with each other and an apparatus with which communication is executed is slightly moved.
For example, when a person or the like passes through a space between apparatuses communicating with each other, and the radio wave temporarily is interrupted, it is desirable that communication is swiftly continued after a radio wave condition is returned. On the other hand, for example, when a user raises portable equipment with which communication is executed to perform some kind of operations and the radio wave is interrupted, there is a high possibility that the user does not expect to continue communication. Thus, it is desirable that a next operation can rather swiftly be executed.
In the aspect of the convenience of a user, a problem arises in that even if the same event, namely the radio wave interruption occurs, a desirable operation of an apparatus is different by a cause of the event.